President Clinton won himself a last-minute stay of execution in the impeachment crisis last night.

With the House of Representatives due to vote on four impeachment charges today, the Republican House Speaker-elect Bob Livingston and his Democratic counterpart, Richard Gephardt, yesterday reached an agreement to postpone the vote because of US military action.

The agreement postpones the near-certainty that Mr Clinton would be impeached, as previously undecided Republicans continued to come out in favour of the four charges against the president.

Postponement could pose organisational headaches for politicians on Capitol Hill, with the Christmas and New Year holidays imminent and the current Congress due to be replaced on January 2.

But the mood in Washington suggested that war would take priority over the first presidential impeachment debate in the Congress since 1868.

"I think it would be awkward to have an impeachment vote during a bombing in Iraq," said House judiciary chairman Henry Hyde, who is scheduled to open the historic debate. But "there are those who think impeachment ought to proceed," he added.

A succession of Republican politicians denounced the timing of the attack on Iraq as a "Wag the Dog" ploy, mirroring the movie satire in which a fictional president concocts a war to divert attention from an Oval Office dalliance.

The Senate majority leader, Trent Lott, and former Bush administration secretary of state, Lawrence Eagleburger, led the attacks on the President.

The timing "smells to high heaven", Mr Eagleburger said. Senator Lott said: "While I have been assured by administration officials that there is no connection with the impeachment process, I cannot support this military action."

"I think this president is shameless in what he will do to stay in office," said one Republican, Congresswoman Tillie Fowler, of Florida. "He will use our military and he will use our foreign policy to remain president."

"Never underestimate a desperate president," said Gerald Solomon, another congressman. "What option is left for getting impeachment off the front page and maybe even postponed?"

The White House responded angrily to the suggestions. The defence secretary, William Cohen, said: "I am prepared to place 30 years of public service on the line to say the only factor that was important in this decision was what was in the American people's best interests."

"The president of the United States makes national security decisions based on the recommendations of his national security advisers and on the best interests of the people of the United States," press secretary Joe Lockhart said.

Before the strikes, the votes had continued to slip away from Mr Clinton. A fresh succession of previously uncommitted Republicans declared in favour of impeachment throughout yesterday, making it all but impossible for Mr Clinton to gather enough allies to overcome the Republicans' 228-207 majority in the House.

If it goes ahead today, the debate is likely to last most of the day and possibly spill into tomorrow, with the votes on all four articles of impeachment taken at the end of all the speeches.

The articles charge Mr Clinton with perjury in the Paula Jones case, perjury in his evidence to the grand jury investigating the Monica Lewinsky affair, perjury in his responses to 81 questions from the judiciary committee and obstruction of justice.

A simple majority on any one article will impeach Mr Clinton and send him to a trial in the 100-member Senate, probably early in the New Year.

At the start of a day in which the concentration on impeachment was powerfully interrupted by news of the worsening Gulf crisis, Republican moderates added their names to the list planning to vote against Mr Clinton.

"He has shattered the trust of the American people by committing perjury, obstructing justice and corroding the rule of law," said Bob Ney of Ohio.

"I am convinced that in this case we do need impeachment as a shield to protect the integrity of our institutions," said another pro-impeachment declarer, Sherwood Boehlert, of New York.

The White House's difficulties were compounded by the addition of liberal Californian Republican congressman Brian Bilbray to the list voting against Mr Clinton.

However, Congressman Michael Castle, of Delaware, spoke in favour of a censure-and-fine Congressional resolution of the sort promoted on Tuesday by the former Republican presidential nominee Bob Dole.

Meanwhile, Vice-President Al Gore, who would succeed Mr Clinton if he was dismissed by the Senate, stood by his boss with a renewed plea for support.

"I believe on Capitol Hill there is still time for Democrats and Republicans to come together and embrace a bipartisan compromise to seek a resolution that is both quick and fair and try to turn away from the bitter partisanship that we have seen so far," he said.

Mr Gore cancelled a campaign trip to New Hampshire, where the first presidential primary is due to take place in 15 months time, to stay in the White House with Mr Clinton, who arrived back in Washington overnight after his trip to the Middle East.

Mr Clinton and his wife Hillary walked arm-in-arm down the steps from Air Force One after landing at Andrews Air Force Base in Maryland.